A link to this site: http://retr0bright.wikispaces.com/ was provided on lugnet by Jonathan Wilson
Fans of vintage computers made with ABS cases and keyboards have discovered a new method for reversing brick yellowing. This new method involves several techniques currently used by Lego fans to remove yellow: Hydrogen Peroxide and sunlight (UV rays). A new paste called retrobright is applied to the plastic and put out in the sun for a day (or under a UV light). Check out the link for dramatic restoration pictures. This may be the quick solution we have been looking for.
Ben